1. Field of the Invention
The present invention relates to an economical and technically available suite of processes for the processing of corn and other grain endosperms in a contained manner to make successive conversions and extractions of useful products for further processing or as end products without the transfer of the endosperm out of the container and extraction system. The ultimate goal of the conversions and extractions is to minimize or eliminate any residual endosperm out of the process container and lower or eliminate interfering particulates from the products for further processing or end use and sale.
Using endosperm only grain products eliminate processing problems involving the fats, oils, proteins and hull particulate matter which cause process problems in the conversion and extraction of desired products of the endosperm and further process problems of the conversion products.
The use of the invention will result in higher value products from the endosperm material and cost savings in the conversions and further processing of the conversion products.
2. Background Information
The processing of grains, particularly corn, to alternate fuel products such as acetone, butanol and, particularly, ethanol is becoming of major importance to the US and world economy. More than 30% of the corn produced in the US goes to ethanol production, and the amount shows a steady increase from 0% 30 years ago. Grains are also becoming an important source of alternate feedstock chemicals to either replace high-priced oil-based products, such as zein plastics and cylodextrins in industrial, food and pharmacological uses, or because of their unique biodegradable and biologically safe (GRAS) nature.
There is, however, a complication over the use of grain products to produce alternate fuels or other chemical products. The commodity prices for the grains are subject to international pressures of rising populations and affluence. This has driven grain prices up and requires new levels of efficiency in processing the grains. A major example of this put 40 of the about 150 dry grind corn ethanol plants into bankruptcy in 2008 when the price of corn rose above the selling price of their two major products, ethanol and the co-product the remaining corn residue called distiller dry grains (DDGS) for animal feed. A similar economic problem existed in 2011 where the corn commodity price for corn and other grains outpaced any rise in fuel ethanol prices.
Some of the corn ethanol producers attempted to broaden their revenue sources by attempting to recover oils and other components downstream of the fermentation and distillation process. Unfortunately, because the whole corn kernel is ground up prior to sugar conversion, fermentation and distillation, the conditions (high temperature/pressure, chemicals) used in the upstream conversion steps can adversely affect the quality and quantity of oils, proteins and other desired components, as well as making the additional product recovery methods inefficient and expensive.
Now several dry milling technologies have become available from companies such as POET, ICM, Inc, MOR Technology LLC and Cereal Process Technology LLC to separate the oil and high quality protein containing germ, as well as the outer hull or bran from the grain kernel in a low energy dry milling process. (DeLine, U.S. Pat. No. 7,524,522; Giguere, U.S. Pat. No. 5,250,313) High quality oil can be recovered from the germ, while the endosperm fraction (starch/protein) continues on through the ethanol production process, making highly efficient use of processing equipment. Only one known major corn ethanol plant is using this dry milling process (instead of the dry grind process). However, because of the general poor economics of the corn/grain ethanol plant investment, and the improved return on investment (ROI) seen by using the dry grind process, the major co-products, except the recovered germ, remain low cost animal feed products comparable to distillers dry grains.
The natural extension to using the Dry Mill process is to pre-process the endosperm and extract clean fermentation sugars for the ethanol process, processing to acetone, butanol and ethanol or other high value alternate energy products. Since the remaining endosperm is still contained within the extraction system, additional high value chemicals contained in the endosperm are easily recovered, such as endosperm proteins and, particularly, the zein proteins. Additional conversion operations are performed on the remaining endosperm to match the range of corn-based chemicals produced in the wet mill corn industry.
The present invention permits the production of high value products from the grain endosperm. These materials can be the primary product, as well as a high value product secondary to the grain-based starch to sugar fermentation product. An example is the production of high value cylodextrins as a secondary product, during the conversion of the endosperm starch to dextrins, oligosaccharides and sugars for subsequent fermentation to energy products. A high value cylodextrin co-product is produced and all the remaining endosperm is converted to fermentation products and high value protein products, removing all need for waste treatment processes associated with a single process cylodextrin production facility.